Classic lobular neoplasia on core biopsy: a clinical and radio-pathologic correlation study with follow-up excision biopsy.

There are no consensus guidelines for the management of lobular neoplasia diagnosed on core biopsy as the highest risk factor for cancer. This study aimed to assess the risk of upgrade (invasive carcinoma or ductal carcinoma in situ) at the site of the lobular neoplasia and any clinical, radiological or pathologic factors associated with the upgrade. We reviewed all cases with a diagnosis of lobular neoplasia on core biopsy from June 2006 to June 2011. Any cases with radio-pathologic discordance, coexistent lesion that required excision (atypical ductal hyperplasia, flat epithelial atypia, duct papilloma or radial scar) or non-classic variant of lobular carcinoma in situ (pleomorphic, mixed ductal and lobular, lobular carcinoma in situ with necrosis) were excluded from the study. Core biopsy indications included calcification in 35 (40%), non-mass like enhancement in 19 (22%), mass lesion in 31 (36%) and mass as well as calcification in two cases (2%). Follow-up excisions were studied for the presence of upgrade. The study cohort included 87 cases and showed an upgrade of 3.4% (95% confidence interval: 1-10%). Three cases showed an upgrade (one ductal carcinoma in situ and two invasive cancers). All upgraded cases were breast imaging-reporting and data system score ≥4 and associated with atypical duct hyperplasia or in situ or invasive cancer in prior or concurrent biopsies in either breast. The number of cores and lobules involved, pagetoid duct involvement, presence of microcalcification in lobular neoplasia, needle gauge and number of cores obtained showed no correlation with the upgrade. Our results suggest that with radio-pathologic concordance and no prior biopsy proven risk for breast cancer, core biopsy finding of lobular neoplasia as the highest risk lesion can be appropriately and safely managed with clinical and radiologic follow-up as an alternative to surgical excision.